Apple rootstock tree named ‘M116’

ABSTRACT

A new and distinct variety of Apple Rootstock Tree named ‘M116’ (nonpatented) characterized by improved resistance to collar rot, mildew and specific replant disease.

Botanical classification: Malus pumila Mill.

Variety denomination: ‘M116’ (nonpatented).

BACKGROUND OF THE INVENTION

In 1962 and 1964, two rootstocks of apple (Malus pumila Mill.),‘Malling-Merton 106’ (nonpatented) (Seed parent) and ‘Malling 27’(nonpatented) (pollen parent), both not patented, were crossed in acultivated area of West Malling, Kent, England. These crosses produced56 (AR10 series) and 59 (AR86 series) seedlings, respectively. After thecompletion of preliminary screening tests, eight seedlings from the AR10series and seven from the AR86 series were selected and propagated in1973 for further evaluation. The vigour of each selection, when grown ashard-pruned hedges in the nursery, was recorded between 1979 and 1983.The potential vigour of the selections when used as rootstocks wasestimated from measurements of the percentage of bark tissue in youngroots, using techniques first described by Beakbane and Thompson (1947)and later modified by Werts et al. (1976). This percentage root bark wasmeasured a number of times between 1974 and 1980 on root samples fromall of the 15 selections. One of the seedlings, ‘AR 86-1-25’(nonpatented) had 52% rootbark.

The ability of these selections to root and establish from hardwoodcuttings was assessed in a minimum of six separate propagation trialsconducted during 10 years. In each test the rooting and subsequentestablishment of hardwood cuttings of each selection were evaluatedusing techniques developed at East Malling Research Station (Howard,1971). For ‘AR86-1-25’ (nonpatented), 63% of cuttings rooted andestablished in the field.

The incidence of mildew (Podosphaera leucotricha) was observed overseveral years on most of the selections growing as hedges and receivingthe standard East Malling Research Station nursery spray programme forpests and diseases. ‘AR86-1-25’ (nonpatented) was found to be relativelyresistant. The selections were scored for resistance to woolly appleaphid (Eriosoma lanigerum) in tests on small potted specimens grownunder glass (Lyth and Watkins, 1981). The rating of ‘AR86-1-25’(nonpatented) was inconclusive but it has since been recorded asresistant. The selections were also scored for resistance to collar-rot(Phytophthora cactorum). ‘AR86-1-25’ (nonpatented) was rated as fairlyresistant. Finally, the field resistance of many of the selections tospecific apple replant disease (SARD) was evaluated (Oehl and Jackson,1980). ‘AR86-1-25’ (nonpatented) was considered resistant.

‘AR86-1-25’ (nonpatented) was first asexually reproduced in 1973 in EastMalling, Kent, England by hardwood cuttings and subsequent generationshave been true to phenotype.

SUMMARY OF THE INVENTION

Rooted cuttings of ‘AR86-1-25’ (nonpatented) were lined out and buddedwith ‘Cox's Orange Pippin’ (nonpatented) in 1974. The maiden trees wereplanted at 3 m×5 m in a replicated design with eight randomised blocksin February 1976 at East Malling. ‘Malling 9 (nonpatented, ‘Malling 26’(nonpatented) and ‘Malling-Merton 106’ (nonpatented) were also lined outand budded with ‘Cox's Orange Pippin’ (nonpatented) in 1974 and plantedin the orchard for comparison. A weed-free strip 2 meters wide wasmaintained beneath the tree rows. The trees were minimally pruned andtrained as open centre bushes. Shoot growth, floral buds, fruit set andyields were recorded on various occasions and the weight of the aboveground portion of each tree recorded at grubbing.

‘AR86-1-25’ (nonpatented) produced trees of similar or slightly smallersize than those on ‘Malling-Merton 106’ (nonpatented) and bore abundantflowers which set fruit efficiently. Yield and fruit grade-out for‘Cox's Orange Pippin’ (nonpatented) on ‘AR86-1-25’ (nonpatented) werebetter than for ‘Malling-Merton 106’ (nonpatented). The 5 yearcumulative total yields of ‘Cox's Orange Pippin’ (nonpatented) werehigher on ‘AR86-1-25’ (nonpatented) than on MM.106 (82 kg compared to 68kg) ‘AR86-1-25’ (nonpatented) exhibits improved resistance to collar rotand specific apple replant disease than ‘Malling-Merton 106’(nonpatented). From the trial evidence, it was concluded that‘AR86-1-25’ (nonpatented) could provide an improved rootstock over‘Malling-Merton 106’ (nonpatented).

In a trial conducted in Hawkes Bay, New Zealand, the number of flowerclusters per unit tree size of Royal ‘Gala’ (nonpatented) has beensimilar for trees on M.116 and MM.106 (7-8 spur and terminal clustersper unit trunk cross sectional area). However, in a trial conducted inCentral Otago, New Zealand, spur abundance was slightly lower for treeson M.116 compared with trees on MM.106. Cumulative yields and yieldefficiencies were similar for Royal ‘Gala’ (nonpatented) trees on ‘M116’(nonpatented) and MM.106 in the Hawkes Bay, New Zealand trial.

‘M116’ (nonpatented) is different from the pollen parent Malling 27 inthat ‘M116’ (nonpatented) has larger flowers and a green-brown bark199A/152A. The bark of ‘Malling 27’ (nonpatented) is brown 200C.

On the basis of the testing carried out in the UK and New Zealand it wasconsidered that ‘AR86-1-25’ (nonpatented) was a commercially usefulrootstock and the Policy Group of the HRI Apple and Pear Breeding Clubdecided to release it under the name M116. ‘M116’ nonpatented) has notbeen observed under all possible environmental conditions and itsphenotype may vary significantly with variations in environment such astemperature, light intensity, and day length, without any variation ingenotype. However, the following unique combination of characteristicsrelating to the use of ‘M116’ (nonpatented) as a rootstock for applevarieties, distinguish ‘M116’ (nonpatented) from all other applevarieties known to the inventor.

-   -   1. Improved resistance to collar rot, mildew and specific apple        replant disease;    -   2. Compatible as a rootstock with all apple varieties tested;    -   3. Improved yields over Malling-Merton 106’ (nonpatented);    -   4. Semi-vigorous growth.

DESCRIPTION OF THE DRAWINGS

‘M116’ (nonpatented) is illustrated by the accompanying photographicdrawings, depicting the plant by the best possible color representationusing conventional color photography techniques. Although the colors inthe photographs may appear different from actual colors due to lightreflectance, they are as accurate as possible by conventionalphotography. The photos are of trees and fruit grown at West Malling,Kent, England.

FIG. 1 shows an overall view of a 3 year old tree.

FIG. 2 is a close up view of the leaves.

FIG. 3 is a close up side view of the fruit.

BOTANICAL DESCRIPTION OF THE PLANT

The following is a detailed botanical description of the new cultivar ofMalus pumila Mill. named ‘M116’. Observations, measurements, values, andcomparisons were collected in West Malling, Kent, England from a 9 yearold tree grown in full sun and on 1 year old shoots.

Terminology used is in accordance with Michael Hickey and Clive King:The Cambridge Illustrated Glossary of Botanical Terms, 2000 CambridgeUniversity Press.

‘M116’ has not been observed under all possible environmentalconditions. The phenotype may vary with variations in the environmentsuch as temperature and light level, without, however, any variance ingenotype. Color references are made to The Royal Horticultural SocietyColour Chart except where general terms of ordinary dictionarysignificance are used.

-   Botanical classification: Malus pumila Mill.-   Variety denomination: ‘M116’ (nonpatented).-   Common name: Apple Rootstock.-   Parentage:    -   -   Pollen parent.—‘Malling 27’ (nonpatented).        -   Seed parent.—‘Malling Merton 106’ (nonpatented).-   Propagation: Hardwood Cuttings and Layering.-   Type: Medium deciduous tree.-   Use: Rootstock.-   Vigour: Vigorous.-   Hardiness: Has been found to tolerate UK climatic conditions with    temperatures typically in the range −5° C. to +30° C. Zone 4-9.-   Root system: Wide spreading.-   Suckering: Initial trials show M.116 has a low tendency to sucker.-   Dwarfing: Slightly more dwarfing that MM.106 but significantly more    vigorous than M.26.-   Precocity: Precocity of flowering and cropping is generally similar    on M.116 and MM.106.-   Tree:    -   -   Habit.—Upright-spreading.-   Trunk:    -   -   Girth.—Medium, moderately rough.        -   Color.—Green-brown 199A/152A.-   Branches:    -   -   Surface texture.—Smooth.        -   Crotch angle.—60 degrees.        -   Color: Green-brown 199A/152A.        -   Form.—Profuse branching.-   Lenticels:    -   -   Quantity.—Medium (upper third of shoot).        -   Length.—0.5-0.7 mm.        -   Width.—0.5 mm.        -   Color.—166D.-   Young shoots:    -   -   Bark colour: Red-brown 183A/200B.        -   Pubescence.—Strong (upper third of shoot).        -   Internode length.—Short — medium 20-25 mm.-   Buds:    -   -   Position of buds in relation to shoot.—Adpressed.        -   Size.—3 mm in length and 2 mm in width.        -   Colour.—Dark brown 200B.        -   Pubescence.—Present.-   Leaves:    -   -   Length.—75-85 mm.        -   Width.—45-55 mm.        -   Shape.—Ovate.        -   Shape of base.—Rounded.        -   Apical angle.—Obtuse.        -   Shape of tip.—Acuminate.        -   Arrangement.—Alternate.        -   Colour of upper side.—Medium green 147A.        -   Colour of lower side.—Light green 137C/D.        -   Pubescence of lower side.—Medium-strong.        -   Serrations of margin.—Bluntly serrate or biserrate.-   Petiole:    -   -   Petiole length: Average 25 mm.        -   Petiole diameter.—2.5 mm.        -   Petiole color.—147C changing to 183C toward the base.        -   Stipule size.—10 mm in length and 2 mm in width.        -   Stipule color.—Upper 143A, lower 148B.-   Flowers:    -   -   Dates of first and full blossoms.—April 21 and 26, near West            Malling, Kent, England. Early-midseason bloom period.        -   Size.—45 mm in diameter.        -   Color: White, RHS 155A both surfaces with pink veins 66D.        -   Petal shape.—Broad ovate.        -   Petal length.—18-20 mm.        -   Petal number.—5.        -   Petal width.—13 mm.        -   Petal margin.—Entire.        -   Petal texture: Smooth.        -   Petal base.—Cuneate.        -   Sepal dimensions.—8-10 mm in length and 2 mm in width.        -   Sepal position.—Reflexed.        -   Stigma position as compared with the anthers.—73% Stigma is            same level as Anthers, 27% slightly lower than Anthers.        -   Stigma color.—1C.        -   Anther size.—10.2 mm.        -   Anther number.—15.        -   Anther colour.—8C.        -   Pollen amount.—Moderate.        -   Pollen colour.—8B.        -   Pollination.—Low self-fertilization, needs pollinizer with            overlapping bloom period.-   Fruit:    -   -   Size medium.—Width 70 mm, height 60 mm.        -   Shape.—Globose conical.        -   Position of maximum diameter.—In the middle.        -   Ribbing.—Distinct rounded ribs. Eye with weak crowning.        -   Size of eye.—Small-medium.        -   Aperture of eye.—Closed.        -   Eye basin.—Medium width (20-25 mm), medium depth (5 mm);            slightly ribbed with beading present in some fruit.        -   Sepals.—Medium length 7.5 mm, 3.5 mm in width, broad and            overlapping.        -   Sepal color.—138 B/C.        -   Stalk.—Medium-long, average 25 mm in length.        -   Stalk color.—175A/177A.        -   Thickness of stalk.—Medium, 2.5 mm in width.        -   Stalk cavity.—Width — broad (35 mm) and depth — medium-deep            (14 mm).        -   Skin.—Smooth, not greasy.        -   Ground colour of skin.—Pale green 145D changing to yellow            10D.        -   Overcolour of skin.—Small area of pale orange flush 39A with            red pink lenticels 39B/50B on the sunny side, lenticels            small and brown 165A but not prominent on the shaded side.        -   Russet.—Very small amount confined within the stalk cavity.        -   Flesh color.—Cream 150D.        -   Fruit in cross section.—Aperture of locules — half-open.        -   Flavor.—Sweet.        -   Aroma.—Mild.        -   Eating quality.—No commercial value.        -   Seed shape.—Broad ovate.        -   Seed colour.—Light brown 177B/200D.-   Resistance to insects: Resistant to woolly apple aphid (Eriosoma    lanigerum).-   Resistance to diseases: Excellent, resistant to collar rot    (Phytophthora cactorum), mildew (Podosphaera leucotricha) and the    specific replant disease.-   Hardiness: Winter hardy, drought and heat tolerant.-   Graft compatibility: ‘M116’ (nonpatented) is fully compatible with    ‘Cox's Orange Pippin’ (nonpatented) and ‘Gala’ (nonpatented). ‘M116’    (nonpatented) exhibits good union between the root-stock and the    grafting stock (scion) with no rejection tendencies observed to    date.

1. A new and distinct variety of Apple Rootstock Tree named ‘M116’(nonpatented) as described and illustrated.